Conformational assignments and a nitrogen inversion process in some 3-acyloxy-1,3-oxazinanes by NMR and X-ray analysis

Citation
Sma. Hashmi et al., Conformational assignments and a nitrogen inversion process in some 3-acyloxy-1,3-oxazinanes by NMR and X-ray analysis, J CHEM S P2, (4), 1999, pp. 877-883
Citations number
22
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
ISSN journal
03009580 → ACNP
Issue
4
Year of publication
1999
Pages
877 - 883
Database
ISI
SICI code
0300-9580(199904):4<877:CAAANI>2.0.ZU;2-L
Abstract
The stereochemistry of the preferred conformers of several 3-acyldxy-1,3-ox azinanes has been established by NMR spectroscopy. A strong anomeric effect stabilizes the conformation having an equatorial orientation of the lone p air on nitrogen. A nitrogen inversion process was found to be the rate-limi ting process in the conformational equilibria. The range of Delta G double dagger values was found to be 60-71 kJ mol(-1). Solid state structures as d etermined by X-ray diffraction confirm the findings of the NMR study.